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Duc Minh Tran

Publications and source records attributed to Duc Minh Tran.

7 recordsLinked to original sources

Materialist: Physically Based Editing Using Single-Image Inverse Rendering

Achieving physically consistent image editing remains a significant challenge in computer vision. Existing image editing methods typically rely on neural networks, which struggle to accurately handle shadows and refractions. Conversely, physics-based inverse rendering often requires multi-view optimization, limiting its practicality in single-image scenarios. In this paper, we propose Materialist, a neural-initialized physically based rendering pipeline for single-image inverse rendering. Unlike previous hybrid methods that use physics to guide neural generation, our method leverages neural networks to predict initial material properties, which are then rigorously optimized via progressive differentiable rendering. Our approach enables a range of applications, including material editing, object insertion, and relighting, while also introducing an effective method for editing material transparency via ray-traced refraction without requiring full scene geometry. Furthermore, our envmap estimation method also achieves competitive performance, further enhancing the accuracy of image editing task. Experiments demonstrate strong performance across synthetic and real-world datasets, excelling even on challenging out-of-domain images.

cs.CV

Controlling Skyrmion Lattice Orientation with Local Magnetic Field Gradients

Precise control over the formation and arrangement of magnetic skyrmion lattices is essential for understanding their emergent behavior and advancing their integration into spintronic and magnonic devices. We report on a simple and minimally invasive technique to nucleate and manipulate skyrmion lattices in soft magnetic CoFeB using single-pass magnetic force microscopy (MFM). By tuning the scan-line spacing to match the intrinsic stripe domain periodicity, the stray field gradient from the MFM tip induces reversible transitions from stripe domains to isolated skyrmions and locally ordered lattices. The resulting skyrmion positions are extracted to compute the local orientational order parameter $ψ_6$, enabling quantitative evaluation of lattice ordering. A systematic improvement in $\langle |ψ_6| \rangle$ is observed with repeated scanning, indicating a transition from a disordered state to ordered hexagonal lattices. Furthermore, we demonstrate that the lattice orientation can be deterministically rotated by changing the scanning direction, as confirmed by both real-space analysis and fast Fourier transformations. This method enables the controlled creation, reordering, and deletion of metastable skyrmion textures on demand. Our approach establishes a practical and accessible platform for studying two-dimensional phase behavior in topological spin systems, offering direct and reconfigurable control over lattice symmetry, order, and orientation.

cond-mat.mes-hall

Correlating on-the-fly Electrical and Optical Skyrmion Readout

Magnetic skyrmions, topologically stabilized spin textures, are promising candidates for future memory devices and non-conventional computing applications due to their enhanced stability, non-linear interactions, and low-power manipulation capabilities. Despite their significant potential, the reliable electrical readout of individual skyrmions remains a fundamental challenge. While magnetic tunnel junctions and anomalous Hall effect (AHE)-based techniques have demonstrated skyrmion detection capabilities, they currently fail to reliably detect single moving skyrmions as required for applications. Our approach leverages thermally activated skyrmions, where a low constant drive current simultaneously generates both skyrmion motion and the Hall voltage necessary for detection. We demonstrate the reliability of this method through real-time correlation between measured Hall voltage signals and direct Kerr microscopy imaging. Two consecutive Hall crosses allow for determining the skyrmion velocity, in accordance to Kerr microscopy videos. We present an analytical formula for the skyrmion AHE readout signal, demonstrating scalability from micrometer to nanometer skyrmions. These advances establish a robust platform for skyrmion-based sensors, counters and unconventional computing systems that depend on precise individual skyrmion control and detection.

cond-mat.mes-hall

Observation of a non-reciprocal skyrmion Hall effect of hybrid chiral skyrmion tubes in synthetic antiferromagnetic multilayers

A hybrid chiral skyrmion tube is a well-known example of a 3D topological spin texture, exhibiting an intriguing chirality transition along the thickness direction. This transition progresses from left-handed to right-handed Néel-type chirality, passing through a Bloch-type intermediate state. Such an exotic spin configuration potentially exhibits distinctly different dynamics from that of the common skyrmion tube that exhibits a homogeneous chirality; yet these dynamics have not been ascertained so far. Here we reveal the distinct features of current-induced dynamics that result from the hybrid chiral skyrmion tube structure in synthetic antiferromagnetic (SyAFM) multilayers. Strikingly, the SyAFM hybrid chiral skyrmion tubes exhibit a non-reciprocal skyrmion Hall effect in the flow regime. The non-reciprocity can even be tuned by the degree of magnetic compensation in the SyAFM systems. Our theoretical modeling qualitatively corroborates that the non-reciprocity stems from the dynamic oscillation of skyrmion helicity during its current-induced motion. The findings highlight the critical role of the internal degrees of freedom of these complex skyrmion tubes for their current-induced dynamics.

cond-mat.mes-hall

Antiferromagnetic Skyrmion Scattering Revealed by Direct Time-Resolved Imaging of Collective Dynamics

Scattering analysis offers a fundamental route to revealing particle interactions with direct implications for device technologies relying on ensembles of particles such as magnetic skyrmions. Here, we directly visualize, in real time, the nanosecond current-driven dynamics of an antiferromagnetic (AFM) skyrmion lattice using element-specific pump-probe X-ray microscopy. By tuning spin-orbit torque relative to local pinning potentials, we reveal two regimes: incoherent flow, where mobile skyrmions scatter from pinned ones, inducing recoil dynamics with 3-20 ns relaxation, and coherent flow, where the lattice translates uniformly. Quantification of the reproducible post-pulse relaxation trajectories via an inverse analyis method based on the Thiele equation yields the nanoscale AFM skyrmion-skyrmion scattering potential, which decays exponentially with a range of 30 nm, in full agreement with micromagnetic simulations. At higher current densities, the lattice exhibits coherent motion free from detectable Hall and inertial effects or dynamical deformation, enabling robust GHz operation. These findings establish a quantitative framework for AFM skyrmion interactions and demonstrate deterministic control of their collective dynamics over billions of cycles even in the incoherent flow regime, thereby paving the way for multi-skyrmion spintronic devices.

cond-mat.mes-hall

Altermagnetic magnon transport in the \textit{d}-wave altermagnet \ch{LuFeO3}

Altermagnets exhibit a spin-split band structure despite having zero net magnetization, leading to special magnonic properties such as anisotropic magnon lifetimes and field-free spin transport. Here, we present a direct experimental demonstration of non-local magnon transport in the \textit{d}-wave altermagnet \ch{LuFeO3}, using both spin Seebeck and spin Hall effect-based injection and detection. We observe a non-local spin signal at zero magnetic field when the transport is along an altermagnetic direction, but not for transport along other directions. The observed sign reversal between two distinct altermagnetic directions in the spin Seebeck response demonstrates the altermagnetic nature of the magnon transport. In contrast, when transport is aligned along or perpendicular to the easy axis, both the first-harmonic signal and the sign-reversal effect vanish, consistent with symmetry-imposed suppression. These findings are supported by atomistic spin dynamics simulations, as well as linear spin wave theory calculations, which explain how our altermagnetic system hosts anisotropic spin Seebeck transport. Our results provide direct evidence of direction-dependent magnon splitting in altermagnets and highlight their potential for field-free magnonic spin transport, offering a promising pathway for low-power spintronic applications.

cond-mat.mtrl-sci

Increased success probability in Hardy's nonlocality: Theory and demonstration

Depending on the way one measures, quantum nonlocality might manifest more visibly. Using basis transformations and interactions on a particle pair, Hardy logically argued that any local hidden variable theory leads to a paradox. Extended from the original work, we introduce a quantum nonlocal scheme for n-particle systems using two distinct approaches. First, a theoretical model is derived with analytical results for Hardy's nonlocality conditions and probability. Second, a quantum simulation using quantum circuits is constructed that matches very well to the analytical theory. When demonstrated on real quantum computers for n=3, we obtain reasonable results compared to theory. Even at macroscopic scales as n grows, the success probability asymptotes 15.6%, which is stronger than previous results.

quant-ph